Abstract:

Abstract:Objective To study the effect of metformin on the growth of  megakaryocytic leukemia cell line Dami and to explore the molecular mechanisms of the inhibitory effect of metformin on the proliferation of  Dami.Methods The Dami cells were cultured and divided into control and 1,2,4,8,16 and 32 mmol/L metformin groups.Then MTT test was performed to detect the inhitory rate of  proliferation of  Dami cells after treated with different concentrations of metformin.Flow cytometry was used to examine the distribution of cell cycle,and Western blotting was carried out to analyze  the expressions of Cdc2 and CylinB1 and the phosphorylation of Cdc2.Results The MTT results showed that compared with control group,the inhibitory rates of proliferation of  the  Dami cells in 32 mmol/L metformin groups at  0,24,48,72 and 96 h (35.1%±2.3%,49.7%±5.1%,78.85±0.9%,79.1%±3.0%%, and 85.2%±3.2%) were significantly increased(P<0.01),Furthermore,after metformin treatment for  72 h,the inhibitory rates of proliferation of the Dami cells in  1,2,4,8,16 and 32 mmol/L metformin groups were (33.8±0.3)%,(51.9±0.2)%,(59.4±1.6)%,(65.5±2.0)%,(75.5±0.9)%,and (79.1±3.0)%,respectively. Metformin inhibited the growth of Dami cells in a time- and dose-dependent manner. The flow cytometry results results revealed that compared with control group,the percentages of Dami cells in G2/M phase in 1,2 and 4 mmol/L metformin groups were increased from (26.0±0.5)% to (38.5±1.5)%,(48.4±1.1)%, and (58.2±2.7)%;there was significant difference in the percentages of   Dami cells in G2/M phase between control group and 4 mmol/L metformin group (P<0.01).Western blotting analysis showed that compared with control group,the expressions of Cdc2 and CyclinB were evidently reduced,the phosophorylation of Cdc2 at Tyr15 was up-regulated,and the phosphorylation at Thr161 was down-regulated.Conclusion Metformin can inhibit the growth of Dami cells and induce G2/M arrest,and its mechanism may be related to inhibiting the activation of Cdc2/CyclinB1 complex.

Key words: metformin, leukemia,megakaryoblastic,acute, cell cycle, Dami cells